Physics Notes (Definitions)

Form 4

Chapter 1: Introduction to Physics

1. Base Quantities- Quantities that cannot be defined in terms of other base quantities
2. Derived Quantities- Quantities that are obtained by combining base quantities
3. Scalar Quantities- Quantities that have only magnitude
4. Vector Quantities- Quantities that have both magnitude and direction
5. Consistency- Ability of an instrument to register same reading when a measurement is repeated
6. Accuracy- Degree of how close a measurement is to the actual value
7. Sensitivity- Ability of an instrument to detect a small change in the quantity measured

Chapter 2: Forces and Motion

1. Speed- Rate of change of distance
2. Velocity- Rate of change of displacement
3. Acceleration- Rate of change of of velocity
4. Deceleration- Rate of decrease in velocity
5. Inertia- Tendency of an object to remain at rest or continue moving
6. Newton's First Law- Inertia
7. Linear Momentum- Product of mass and velocity
8. Principle of Conservation of Momentum- Total momentum of a system remains unchanged if no external force acts on the system
9. Force- Anything that changes the state of rest or motion of an object moving in a straight line
10. Newton's 2nd Law- Acceleration, a, is directly proportional to the net force acting on it, F, and inversely proportional to its mass, m
11. Impulse- Change in momentum
12. Impulsive force- Rate of change of momentum
13. Gravitational Force- Pulled force towards centre of earth
14. Free fall- Object falling under the force of gravity only
15. Gravitational Acceleration- Acceleration of falling object due to gravity
16. Gravitational Field- Region around the earth in which an object experience gravitational attraction
17. Resultant Force- Single force that represents the combined effect of two or more forces
18. Unbalanced Force- Produce an acceleration to the object
19 Forces in Equilibrium- When resulting force acting on the object is zero
20. Newton's 3rd Law- To every action, there is an equal but opposite direction
21. Work- Product of force, F, and its displacement, s, in the direction of applied force
22. Energy- Ability to do work
23. Gravitational Potential Energy- Energy stored in object due to its position in a force field
24. Kinetic Energy- Energy possessed by an object due to its motion
25.
26. Power- Amount of work done per second
27. Efficiency- Percentage of the energy input that is transferred into useful energy
28. Elasticity- Ability to return to its original shape after external force is removed
29. Elastic Limit- Maximum force that can be applied to a spring such that the spring will be able to restored to its original length when the force is removed
30. Hooke's Law- Extension of a spring is directly proportional to the applied force
31. Spring Constant- Force that is required to produce one unit extension of the spring
32.  Elastic Potential Energy- Energy stored in a spring when it is extended or compressed

Chapter 3: Force and Pressure

1. Pressure- Force acted on a unit of surface area
2. Atmospheric Pressure- Weight of the air on the Earth's surface
3. Gas Pressure- Force exerted by gas molecules as they collide with the walls of their container
4. Pascal's Principle- When pressure is applied to an enclosed fluid, pressure will be transmitted equally throughout the whole enclosed fluid
5. Buoyant Force- Upward force resulting from an object being wholly or partially immersed in a fluid
6. Archimedes' Principle- When an object is immersed in a fluid, buoyant force on the object is equal to the weight of fluid displaced by the object
7. Bernoulli's Principle- Pressure of a moving liquid decreases as the speed of the fluid increases

Chapter 4: Heat

1. Temperature- Degree of hotness of an object
2. Heat- Energy transferred from hot to cold object
3. Thermal equilibrium- Rates of heat transfer between two objects is equal
4. Thermometric Property- Subtance which is sensitive and varies linearly with  changes in temperature of the material
5. Ice Point- Temperature of pure melting ice
6. Steam Point- Temperature of water steam that is boiling under standard atmospheric pressure
7. Heat Capacity- Amount of heat that must be supplied to increase its temperature by 1*C
8. Specific Heat Capacity- Amount of heat required to to increase temperature by 1*C for 1 kg mass of subtance
9. Latent Heat- Heat absorbed or released at a constant temperature during change of phase
10. Specific Latent Heat of Fusion- Amount of heat required to change the phase of 1kg of a substance from solid to liquid
11. Specific Latent Heat of Vaporisation- Heat required to change phase of 1kg of a substance from liquid to gas
12.  Specific Latent Heat-  Heat required to change phase of 1kg of a substance
13. Boyle's Law- Pressure is inversely proportional to its volume when temperature is kept constant
14. Charles' Law- Volume of gas is directly proportional to its absolute temperature when its pressure is kept constant
15. Pressure Law- Pressure of gas is directly proportional to its absolute temperature when volume is kept constant